Apparatus for detecting and warning of under/over-inflation of inflatable cushions

ABSTRACT

An apparatus intended to reduce or eliminate human tissue damage caused by under- or over-inflation of air-filled bodily support cushions by sensing the internal air pressure and alerting the user to that pressure. The apparatus uses a simple, inexpensive, analog or digital gauge connected to the exterior of cushions, such as those cushions used on the seats of wheelchairs. It can also use an audible warning activated by the gauge, indicating cushion pressure outside a pre-set range of values. The apparatus also includes a valve that can be used to release or add pressure to the cushion. Further, the length of the apparatus can be varied so that the outlet valve can be easily accessed and/or the gauge can be easily viewed.

FIELD OF INVENTION

[0001] This invention relates primarily to accessories for inflatableseat and body support systems-more particularly, the function of andaccessories to inflatable cushioning systems associated withwheelchairs, cushions for beds, other body-supporting medical devices,and orthopedic devices.

BACKGROUND OF THE INVENTION

[0002] The following represents a list of known related art: Reference:Issued to: Date of Issue: U.S. Pat. No. 5,963,997 Hagopian Oct. 12, 1999U.S. Pat. No. 4,643,481 Saloff Feb. 17, 1987

[0003] An ongoing problem associated with extended use of wheelchairs orsimilar supporting medical devices is the development of sores andtissue damage, caused by constant, long term pressure on body tissue.Simply put, damage occurs in body tissue that has been subjected toexternal pressure that restricts blood flow to tissues. These sores arealso known as bedsores, pressure ulcers, pressure sores, and decubitusulcers; this damage can even cause infection, requiring hospitalizationand/or medical treatment.

[0004] To lessen pressure on body tissues and prevent this tissuedamage, people who are confined to or are regular users of wheelchairsor similar supportive devices or beds commonly use supportive cushions.For wheelchair users, these cushions are used on the backs and/or seatsof their wheelchairs. A common type of cushion contains an adjustable,inflatable bladder or bladders to support the user.

[0005] However, these cushions themselves can cause the same tissuedamage, due primarily to under- or over-inflation of the cushionbladder(s). Moreover, users with impaired sensation may not be aware ofthe under/over-inflation of the cushion that can lead to tissue damage.This is particularly true with people who try to be as self-reliant aspossible and do not have full-time medical assistance or caregivers.

[0006] Many have attempted to overcome this problem using variouscushion designs, attempting to relieve pressure, but have been largelyunsuccessful, or, at best, partially successful. Others have usedcomplex means of regulating pressure, including expensive, bulky, andcomplicated powered inflation devices that must be continually attachedand electrically powered.

[0007] The short length of existing valve stems on commerciallyavailable inflatable cushioning systems associated with wheelchairs,cushions for beds, other body-supporting medical devices, and orthopedicdevices makes it difficult to add air to the cushion bladders. In mostcases, the user must get off the cushion in order for the existing valvestem to be accessed to either add or release air from the cushionbladder. This can be a time consuming and difficult proposition,particularly for those with limited sensation, mobility and/or strength.

[0008] The claimed invention attempts to solve these problems using asimple means of alerting the user to under and/or over-inflation ofthese cushions by measuring the internal air pressure of the cushion andindicating under or over-inflation to the user or their caregivers orassistants. Further, the claimed invention can utilize longer air hoses,so that the outlet valve on the invention can be easily accessed andutilized by the user or an assistant.

SUMMARY AND ADVANTAGES OF THE INVENTION

[0009] This apparatus for detecting and warning of under/over-inflationof inflatable cushions is a simple digital or analog gauge that isattached to an existing inflatable cushion—to the existing valve stem—onall commonly commercially available inflatable cushioning systemsassociated with wheelchairs, cushions for beds, other body-supportingmedical devices, and orthopedic devices. The gauge indicates the airpressure inside the cushion, and warns the user of under orover-inflation. The apparatus actuates the cushion's existing valve,allowing air to flow freely out of the cushion and allowing thecushion's air pressure to be measured. The apparatus also includes anoutlet valve, which can be attached to a pump or be manually operated toincrease or decrease air pressure inside the cushion.

[0010] The apparatus' gauge may be located in a variety of places byusing variable lengths of air hose connecting the apparatus' gauge tothe cushion's valve stem, or the air hose connecting the gauge to theoutlet valve of the apparatus. Gauge placement can range from placementimmediately adjacent to the cushion, using a short air hose, to gaugeplacement near the user's mouth, simply by increasing the length of theconnecting air hose. The gauge may also be placed near the user's handor the armrest of the wheelchair, to provide easy access and visibility.

[0011] Warning to the user can result from three methods: a visibleanalog gauge with a dial showing cushion pressure, a digital gauge witha pressure reading, or a gauge which produces an audible sound, alertingthe user to pressure variations outside of a pre-set range.

[0012] When the apparatus uses an audible warning gauge, the user canset upper and/or lower values for the desired pressure in the cushion.Once the pre-set value is exceeded, in the case of over-inflation, anaudible warning sounds. If the pressure falls below a pre-set value, asin the case of under-inflation, an audible warning sounds. The user thenmanually adjusts the pressure by letting air out or adding air manuallyor by pump.

[0013] The apparatus has a means of adding or releasing pressure fromthe cushion. An outlet valve—opposite the end connecting the apparatusto the existing cushion—can be used to attach inflation devices, such aspumps, or it can allow air in or out of the cushion when activatedmanually by the user.

[0014] This apparatus for detecting and warning of under/over-inflationof inflatable cushions overcomes an inherent problem of inflatablecushions in that it detects the state of under- or over-inflation ofinflatable, supportive cushioning systems associated with wheelchairs,cushions for beds, other body-supporting medical devices, and orthopedicdevices.

[0015] Additionally, it overcomes a second inherent problem in theexisting art in that it warns the cushion's user of states of under- orover-inflation.

[0016] Additionally, this apparatus overcomes the complexity, expense,bulkiness, and electrical power requirements of other inflation systemsby using a simple visible or audible pressure gauge and valve system.

[0017] Additionally, this apparatus allows for use of cushions withoutsacrificing utility of the cushions and their associated accessories.The apparatus' outlet valve can be used to add or release pressureto/from the cushion's interior bladder, just as was possible with theoriginal cushion. The apparatus allows for the use of the inflationpumps which are supplied with the original cushions, or other types ofpumps, depending on the configuration of the outlet valve and outletvalve stem.

[0018] Additionally, the placement of invented apparatus' outlet valveis useful for adding or releasing pressure to/from the cushion while thecushion is in use and increases the utility of the cushion. That is,since the outlet valve can be placed where it is accessible to theuser—whether near the user's hands, mouth, or near the arm rest of awheelchair, for example—the apparatus increases the utility of theexisting cushion. Rather than forcing the user to get off of the cushionin order to add or release pressure to/from the cushion's interiorbladder, the user can perform these tasks while the cushion is in use.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 shows the first embodiment of the invented apparatus with asimple analog dial gauge, unconnected to a cushion. An arrow indicatedoutward airflow from the cushion.

[0020]FIG. 2 is a view of the invention attached to a common,commercially available wheelchair cushion, showing the inventedapparatus configured with an analog gauge (as in the first embodiment),and attached to the existing valve stem of a cushion. The cushion in thedrawing is similar to a commercially available and representativewheelchair cushion.

[0021]FIG. 3 shows a close up, cut-away view of one end of the inventedapparatus, where it attaches to the existing cushion, illustrating howthe invented apparatus would be configured if the existing cushion useda Schrader type valve.

[0022]FIG. 4 shows a close up, cut-away view of one end of the inventedapparatus, where it attaches to the existing cushion, illustrating howthe invented apparatus would be configured if the existing cushion useda Presta type valve and the invented apparatus' end was a flexible hosewhich slid over the end of the existing cushion's valve stem.

[0023]FIG. 5 shows the invented apparatus, with a long tube between thegauge itself and the end of the invented apparatus, where it attaches toan existing cushion. This illustrates the third embodiment of theinvented apparatus.

[0024]FIGS. 6 and 7 are, respectively, head-on and longitudinal cut-awayviews of close ups of the end of the invented apparatus, opposite fromwhere it attaches to a cushion. This end of the invented apparatus iswhere a pump may be connected to the invented apparatus. These viewsassume the invented apparatus uses a Schrader type valve as an outletvalve, and illustrate the fourth embodiment of the invented apparatus.

DESCRIPTION OF THE INVENTION

[0025] Referring particularly to the drawings, FIG. 1 shows the firstembodiment of the invented apparatus (disconnected from the cushion'svalve stem). An arrow indicated outward airflow from the cushion.

[0026] The invented apparatus has four basic, functional parts in itsfirst preferred embodiment. It has an end which physically connects tothe cushion's existing valve stem and actuates that existing valve stem.This functional part is called the cushion connection end 1.

[0027] The second functional part is the pressure-measuring gauge 2 andits associated gauge housing 3. A third functional part is the air hose4 connecting the cushion connection end 1 to the pressure-measuringgauge 2. The fourth basic, function part is opposite the cushionconnection end 1 and it is called the pump connection end 5.

[0028] The pump connection end 5 provides a point of attachment forpumps or other means of adding air to the cushion or releasing air fromthe cushion. It is shown in FIG. 1 to be opposite the cushion connectionend, at an approximately 180 degree angle from the cushion connectionend 1, but can be at a right angle to the cushion connection end 1 aswell. It is fluidly connected to the pressure-measuring gauge 2, the airhose 4, and the cushion connection end 1.

[0029] The pump connection end 5 is meant to be identical inconfiguration and function to the existing valve stem of the cushion, sothat any pump or inflation means normally used with the cushion aspurchased—or inflation means or accessory sold by the cushionmanufacturer—can be attached to and used with the invented apparatus.

[0030]FIG. 2 shows a completed, final installed configuration of thefirst embodiment of the invented apparatus. Note that the gauge face isturned upright, so that the user of the cushion or an assistant can readthe gauge's measurement.

[0031] The cushion, used for solely for illustrative purposes, in FIG.2, is similar in makeup to most commercially available wheelchaircushions, in that these cushions are manually inflated from an existingvalve stem, which typically emerges from the side or corner of mostcommercially available cushions.

[0032] The invented apparatus can be attached to the cushion's existingvalve by several means. Suitable means for fluidly connecting theinvented apparatus are well known in the technical field. First, theinvented apparatus may be screwed onto the existing valve stem. Thistype of standard valve is most typically called a Schrader valve. Somecommercially available cushions use this standardized valve stem,similar in construction to most bicycle and automobile tires. Anillustrated example of a threaded-end, standard valve stem configurationis shown in U.S. Pat. No. 6,374,666 (particularly that '666's FIG. 1,valve stem 12), which is incorporated herein by reference. If thecushion's existing valve is a Schrader type valve, screwing the inventedapparatus onto the end of the existing valve stem will provide anair-tight seal with the existing valve, actuate the cushion's existingvalve by compressing the Schrader valve's plunger inward, and allowfluid from the inside of the cushion to flow freely through the air hose4 and to the pressure-measuring gauge 2, and activate thepressure-measuring gauge 2 in the invented apparatus. With this type ofconfiguration, the interior diameter dimension of the cushion connectionend 1 is larger than the exterior diameter dimension of the existingvalve stem, allowing for the cushion connection end 1 to be screwed ontoand over the end of the existing valve stem.

[0033] By way of illustration, and referring to FIG. 3, a cutaway viewis shown of cushion connection end 1, used when the cushion's existingvalve stem is of the Schrader type.

[0034] The cushion connection end's opening 6 is to be screwed onto theexisting cushion valve stem's threaded end, by means of internal threads7. The interior diameter dimension of these internal threads will matchthe exterior diameter dimension of the existing valve stem so that thecushion connection end 1 to be screwed onto and over the end of theexisting valve stem. Once the cushion connection end 1 is screwed ontoand over the end of the existing valve stem, the plunger inside theexisting cushion valve stem is then engaged and actuated by a plungerpin 8, which opens the cushion's valve, allowing air to flow freely fromthe cushion's existing valve stem, through to the invented apparatus'pressure-measuring gauge 2. Once again, this method is well known in thetechnical field and prior art, and illustrated by U.S. Pat. No.6,374,666 (particularly '666's FIG. 4, 72).

[0035] An alternative means for fluidly connecting the inventedapparatus is also well known in the technical field, although the valvetype is somewhat less commonly used: the Presta type valve. It is wellknown in the prior art that the Presta type valve is opened and closedby screwing the Presta valve open or closed. There are two alternativeways for the invented apparatus to connect to a Presta type valve.

[0036] First, there are commercially available adapters thatlongitudinally attach to Presta type valves, causing them tofunctionally operate as Schrader type valves. These adapters fit overopen Presta valve stems, and provide a Schrader type secondary valve,plunger, and threaded end that can then be operated normally, in placeof the Presta valve, as noted above.

[0037] Second, an even more simple connection to an existing Presta typevalve can be made. The existing Presta valve may be opened, and a snug,flexible hose can be slid over the existing valve stem, creating an airtight seal around the existing valve stem and completely covering theend of the existing valve stem. This is illustrated in FIG. 4, whichshows a cut-away view of the cushion connection end 1, slid over anopened, existing Presta valve stem 9.

[0038] Regardless of whether the Presta type valve or Schrader typevalve is used in the cushion's existing valve stem, the inventedapparatus is a single embodiment because both valve types and methods ofactuating the valves are well known in the technical field andconstitute prior art.

[0039] The pump connection end 5, as shown in FIG. 1, uses a Schradertype or Presta type valve, for connection to an external pump, so thatair can be added to the cushion while the invented apparatus isattached. The valve type choice for the pump connection end 5 will, inmost cases, match the valve type used in the cushion's existing valvestem.

[0040] The gauge face is shown in the center of the body of the inventedapparatus. This is not a necessary part of any embodiment, nor is theshape of the gauge or body of the invented apparatus. However,regardless of the shape or look of the gauge or body, the gauge isintended to be visible and readable from a distance of several feet, sothat the user of the cushion or a caregiver or assistant can read thegauge's measurement without needing to be overly close to the gauge.

[0041] The first embodiment of the invented apparatus uses an analoggauge of type well known in the technical field, most commonly referredto as a Bourdon tube pressure gauge.

[0042] A second embodiment uses a small digital pressure gauge, in placeof the analog gauge used in the first embodiment. A digital gauge can beused in place of an analog gauge while the connections and ultimatefunctionality of the invented apparatus remains the same. Morespecifically, from an operational standpoint, the invented apparatuswill function in the same fashion, regardless of whether the gaugereadout is digital or analog. Further, regardless of whether the gaugeis analog or digital, the pump connection end and the cushion connectionend will be the same, as discussed and described above. The secondembodiment is not shown in the figures.

[0043] Referring to FIG. 5, a third embodiment of the invented apparatusis shown, wherein the length and flexibility of air hose 4 from thecushion connection end 1 to the actual gauge housing 3, is sufficientsuch that pressure-measuring gauge 2 itself may be mounted or placed ina position such that the gauge is more easily read or the pumpconnection end 5 is more easily accessed. A possible use for this thirdembodiment is to connect the gauge to the armrest of a wheelchair.

[0044] A fourth embodiment effects only the pump connection end 5 of theinvented apparatus. It is an alteration of the pump connection end 5which will allow the user to actuate the valve in the pump connectionend 5 so that air pressure can be released from the cushion's interiorbladder, should the user so desire or should the air pressure reading onthe invented apparatus' pressure-measuring gauge 2 be, in the user'sopinion, too high. Of course, this embodiment is only used if the pumpconnection end 5 uses a Schrader type valve, rather than a Presta valve.There are two primary ways of accomplishing this actuation of the valveon the pump connection end 5. Since they are functionally the same, andeither will constitute the same embodiment.

[0045] First, referring to FIG. 6, which is a close up of the pumpconnection end 5, air pressure is released from the cushion by manuallypushing a sliding thumb lever 10 toward the pressure-measuring gauge 2.The sliding thumb lever 10 is connectedly attached to the Schrader typeoutlet valve plunger 11 via a thin connector piece 12 of rigid plasticor metal, which is fitted through—and slides back in forth in—a slit inthe outer layer of the valve stem 13. The slit in the outer layer of thevalve stem has two thin, flexible, parallel gaskets made of rubber or arubber-like material that seal around the connector piece 12, so that noair escapes around the connector piece 12, regardless of its position.When the sliding thumb lever is slid toward the gauge's face, thevalve's plunger is physically depressed and air is released from thevalve. The valve's existing spring (which is a standard part of Schradervalves and which hold the valve closed under normal circumstances) willpush the connector piece 12 back to its starting position automaticallyand thereby close the valve. The Schrader type outlet valve plunger pin14, can be seen on FIG. 7. The threaded exterior 15, that is standard onSchrader type valve stems, can be seen on FIG. 7.

[0046] Second, another way of actuating the outlet valve on the pumpconnection end 5 uses a thumb-twisted lever that activates a twistvalve. Twist valves are well known in the prior art and well known inthe technical field. By turning the thumb lever, the valve is opened orclosed.

[0047] A fifth embodiment of the invented apparatus is not shown in thefigures. An audible buzzer or other sound-making device can be addedinside the gauge housing 3 of the invented apparatus and electronicallyconnected to the gauge mechanism so that the buzzer or sound-makingdevice activates whenever the gauge reading is outside of a certainpreset range of values. Audible buzzers or sound-emitting devices arecommonly used as indicators of pressure variance and are readilyavailable commercially, particularly in the sporting goods industry, andparticularly with respect to diving watches and equipment. With thisembodiment, the user or his or her assistant can set the range ofacceptable pressure values for the internal cushion pressure, so thatthe sound-making device activates when the pressure is outside itsacceptable range.

I claim:
 1. An apparatus for detecting and warning of under- orover-inflation of inflatable cushions, comprising: a fluid pressuremeasuring gauge connectedly attachable to the exterior of said cushion,and in fluid communication with the interior bladder of said cushion. 2.An apparatus, as in claim 1, wherein said gauge further comprises ananalog readout, which visibly indicates an approximate fluid pressureinside said cushion.
 3. An apparatus, as in claim 1, wherein said gaugefurther comprises a digital readout, which visibly indicates anapproximate fluid pressure inside said cushion.
 4. An apparatus, as inclaims 1, 2, or 3, wherein said gauge is mounted in such a position thatthe readout of said gauge is visible to the user of said cushion.
 5. Anapparatus, as in claims 1, 2, or 3, further comprising an audibleannunciator electronically connected to said gauge that indicates incase the fluid pressure inside said cushion deviates from apredetermined range of values.
 6. An apparatus, as in claim 1, furthercomprising a valve for releasing fluid from said bladder in said cushionand for adding fluid to said bladder in said cushion.
 7. An apparatus,as in claim 6, wherein said valve is mounted in such a position thatfluid can be added to or removed from said cushion without the user ofsaid cushion getting off of said cushion.
 8. An apparatus, as in claims6 or 7, wherein said gauge is mounted in such a position that thereadout of said gauge is visible to the user of said cushion.
 9. Anapparatus, as in claims 6 or 7, further comprising an audibleannunciator electronically connected to said gauge that indicates incase the fluid pressure inside said cushion deviates from apredetermined range of values.
 10. An method for detecting and warningof under- or over-inflation of inflatable cushions, which comprises: a)measuring fluid pressure present inside the bladder of an inflatablecushion; b) communicating to the user of said cushion when said measuredfluid pressure inside said cushion is above or below a predeterminedrange of inflated pressure.
 11. A method, as in claim 10, wherein saidcommunicating function comprises audible communication.
 12. A cushionair pressure detecting and warning apparatus which comprises: a)fluidly, but removeably, attaching an air hose to an inflatable cushion;b) fluidly connecting a fluid pressure measuring gauge to said air hose;and c) fluidly connecting an outlet valve to both said gauge and saidair hose, so that said outlet valve can be used to release or add fluidpressure from or to said cushion.